It is only the fifth definitive coin portrait to have been created during the Queen's reign, and the first new picture since 1998.

It has been designed by Jody Clark - the youngest of five designers who have created the portraits of the Queen for UK circulating coins during her 63-year reign.

The slider below compares the queen's first coin portrait with today's up-to-date design:

The Queen's first coin portrait from 1953 [left] and today's new version

The 2015 portrait shows a side profile of the Queen wearing a crown and drop earrings. Her first coin portrait, issued in 1953, depicted the monarch wearing a wreath of laurel, which was thought to reflect the country's optimism as it greeted a new queen in the post-Second World War era.

There were estimated to be around 28.9 billion UK coins in circulation at March 31 last year, with a total face value of more than £4 billion.

Chief engraver at the Royal Mint Gordon Summers described the design task as "probably one of the most difficult things for any artist or sculptor to do".

Clark, the designer, said: "I really liked the four previous coin portraits - each one is strong in its own way.

"I hope that I've done Her Majesty justice and captured her as I intended, in a fitting representation. The news that my design had been chosen was quite overwhelming, and I still can't quite believe that my royal portrait will be featured on millions of coins, playing a small part in the Royal Mint's 1,000-year history."

Mr Clark, who is originally from the Lake District and who celebrated his 34th birthday yesterday, said his family are "really proud", adding: "They've had to keep quiet about this.

"It's going to be hard to top this. It's going to take a while to sink in."

He said his top priority was to create an "accurate" representation of the Queen.

He added: "I'm really happy with how it's turned out. I can only hope everyone appreciates it."

QUEEN ELIZABETH II ON COINS OVER THE YEARS

Kevin Clancy, director of the Royal Mint Museum, said the judging panel's decision was "pretty unanimous" and added that this latest portrait is "astonishingly significant". He said it had "a good likeness and a dignified likeness".

Mr Clancy said there was not a "strict brief" sent to potential designers.

Mr Clark's portrayal of the Queen, wearing the Royal Diamond Diadem crown worn for her Coronation, was selected in a closed competition organised by the Royal Mint Advisory Committee (RMAC), a consultative panel to HM Treasury comprising experts from such fields as history, sculpture, architecture, art and design.

A number of specialist designers from across Britain were invited to submit their own interpretations of the Queen's portrait under anonymous cover, and each one was judged on its merits and suitability before the winning artwork was recommended to the Chancellor and, ultimately, the Queen for approval.

Adam Lawrence, chief executive of the Royal Mint, said: "This change of royal portrait will make 2015 a vintage year for UK coins, and it will be hugely exciting for us all to see the new design appear on the coins we use every day.

"Jody's achievement is something that we can celebrate as a proud moment for the Royal Mint.

"Capturing a portrait on the surface of a coin demands the utmost skill, and is one of the most challenging disciplines of the coin designer's art.

"The last Royal Mint engraver to be commissioned to undertake a royal portrait was George William de Saulles, who engraved the portrait of Edward VII which first appeared on the coinage in 1902."

Coins featuring the new effigy go into production today and the public are being urged to keep an eye on their coins later this year when it will start to appear.